When is the best time to observe 59 Serpentis?

59 Serpentis is best observed from May through July, with peak visibility during June when it transits around midnight in the Northern Hemisphere.

Where is 59 Serpentis located in the sky?

59 Serpentis lies in the constellation Serpens at right ascension 18h 27m and declination +00° 12′.

What telescope do I need to split 59 Serpentis?

Splitting 59 Serpentis requires an aperture of roughly 100 mm or larger — the components are separated by about 3.9″ at magnitudes near 5.2. Larger apertures and steady seeing help resolve the pair cleanly.

59 Serpentis — Double Star in Serpens

Observable Double Star Good (58/100)

Sep: 3.9", Companion: mag 7.6

Magnitude 4.9–5.9^m DoubleStar Serpens (Ser) Visible

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Observe

1Physical Properties

Magnitude 5.21

Spectral Type G0III+A6V giant

Star Color Yellow (B-V 0.50)

Distance 204 ly

2Position & Identifiers

RA 18h 27m 12.5s

Dec +00° 11' 46.0"

Constellation Serpens (Ser)

HR 6918

HIP 90441

HD 169985

SAO 123497

Flamsteed 59 Ser

Variable ID d Ser

Double Cat 11353

SIMBAD

3How easy to split?

Primary 5.2 mag Companion 7.6 mag Separation 3.9″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Medium	Medium	Medium
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season May – Jul (peak: Jun)

5Multiple Star System Triple

Components 3 (triple)

Component IDs AB

Separation 3.9″

Companion Mag 7.6

Companion Sp A6V

Position Angle 322°

Star Colors A: Yellow B: Yellow-white

Discoverer STF2316

Notes

AB physical. B is F5V, vsini =<54k/s. Component P, vsini 80:k/s.

Separation over time

Measured 1822 → 2018 (196 y)

Separation drift 3.7" → 3.9" (+0.20")

Rate +0.0010" / y

PA drift 312° → 322° (+10°, +0.051°/y)

Essentially fixed on human timescales — the same view your grandchildren will see.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.

Eyepiece View

Telescope Eyepiece

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80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 5.2 · B: 7.6 · Sep: 3.9″ · PA: 322° · N up, E right

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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Size Comparison

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Spectral Classification

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Hertzsprung-Russell Diagram

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Stellar Lifecycle

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Blackbody Spectrum

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Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

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Stellar Fusion

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14Stellar Notes

Variable Star

ADS 11353A, 4.9 - 5.9v.

Spectroscopic Binary

ADS 11353A is triple spectroscopic system with periods 385 and 1.8505205d. vsini of A-type component 270k/s, of G-type, | 80:k/s. Comp. B may also be SB, and third visual component P at 0.1" from A may be one of the components of the long | period pair. ADS 11353A, 1.8505, K 90k/s, asini 2.29. ADS 11353Ap?, 386.0d, K 28k/s, V0 -23.3k/s, asini 731. | Companion with sep. 0.25" seen only on 1976.61; unresolved at four other epochs between 1976.3 and 1979.5 (McAlister | and Hartkopf). | 28k/s, V0 -23.3k/s, asini 731.

Dynamical

0.007".

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